SKOWHEGAN — The man accused of killing Rita St. Peter in Anson 31 years ago fought for a second time on Thursday to be released from jail until his trial, but was denied.

Maine Supreme Judicial Court Justice Joseph Jabar upheld a lower court’s decision when he ordered Jay S. Mercier, 56, of Industry, to continue being held without bail, based on the nature of the crime and the evidence against him.

“I’m not saying he’s guilty here because of the evidence. What I’m saying is there is significant evidence,” Jabar said.

In front of him sat five members of St. Peter’s family, Assistant Attorney General Andrew Benson, Maine State Police Detective Bryant Jacques, Mercier and defense attorneys John Alsop and John Martin.

The Supreme Judicial Court is Maine’s highest court and the court of final appeal. Its job is to decide appeals on questions of law that arise in civil and criminal cases.

Mercier is accused of murder, which carries the state’s weightiest sentence — 25 years to life in prison.

Though he was a suspect from the beginning in July 1980, it wasn’t until Sept. 28 that he was arrested and charged with killing St. Peter, who was 20. The prosecution claims that he sexually assaulted her, bludgeoned her on the head with a weapon akin to a tire iron and partially ran her over with his pickup truck on a field road off Campground Road.

The hearing Thursday in Superior Court focused on whether Judge John Nivison was mistaken in his previous decision on Dec. 5 to hold Mercier without bail until his trial.

Defense attorney Martin argued that the lower court’s finding was clearly erroneous because it was based on a police affidavit that was not proven reliable. The state did not demonstrate the credibility of the people interviewed and included in the court paperwork, which was put together in order to charge Mercier, he said.

“This is simply Detective Jacques cutting and pasting his police report and providing it to the court,” he said.

Martin also argued that Mercier has not fled the area, though he has been interviewed many times by police over the last 31 years. He said Mercier has only a minor criminal record and has family to tie him to Maine. Though he is on disability, he appears to be in good mental health, he said.

“Mr. Mercier is even a perfect candidate for this type of bail,” he said. “It’s a good demonstration of why the legislature allowed this discretionary bail to exist.”

Benson replied that the affidavit is reliable because it included information from named, trustworthy sources, such as Dr. Henry Ryan, Maine’s chief medical examiner at the time, and forensic scientist Alicia Wilcox of the Maine State Police Crime Laboratory.

Wilcox determined that the tires on Mercier’s pickup — which had different types of tires on the front and back — matched the tracks at the scene of the crime, the affidavit states.

Forensic DNA analyst Cathy MacMillan also determined that Mercier’s DNA matched the semen found inside St. Peter, according to the affidavit. The probability of someone else carrying the same DNA is less than one in 300 billion.

Benson argued for the sources’ reliability, saying, “We’re not talking about these shadowy, unnamed figures.”

He also argued that Mercier has no stable employment to keep him in the area and does not have strong family ties, as he is estranged from his sister, and his mother is in a nursing home. He said his criminal history was not minor but in fact fairly significant, with a couple operating under the influence and assault convictions.

“Mr. Mercier is hardly an ideal candidate to be released on bail,” he said. “Now, more than any other time, he has every incentive not to appear.”

Jabar concluded that, while evidence can be challenged, the sources in the affidavit are reliable in the sense that what is written in the affidavit is what they would say in court.

“There’s plenty of evidence from witnesses who are named,” he said.

In the end, he said his decision to keep Mercier in jail was not based so much on Mercier’s employment, family or criminal history. It was more based on the nature and circumstances of the crime and the evidence, which “weighs heavily against the defendant.”